It is wonderful to have a group of singers belting a chorus along with you especially with harmonies.....what is not wonderful is, as has been mentioned earlier,is when it gets taken over.

I found myself in that situation recently and found it a bit distracting. All was going well but one person sitting near me was about three words ahead in the refrain and doing their own thing and it was putting me off. My initial reaction was to put up a hand and stop them......but......I was there as a guest singer and in some fine company and thought it better not to resort to diva-ish behaviour. However, I found a way of dealing with it without making too much of a fuss. I just played about with the refrain, stretching notes putting in ornamentation etc til the culprit was keeping up with me and not the other way around.